TaqMan probe real-time polymerase chain reaction assay for the quantification of canine DNA in chicken nugget

ABSTRACT

This paper describes a short-amplicon-based TaqMan probe quantitative real-time PCR (qPCR) assay for the quantitative detection of canine meat in chicken nuggets, which are very popular across the world, including Malaysia. The assay targeted a 100-bp fragment of canine cytb gene using a canine-specific primer and TaqMan probe. Specificity against 10 different animals and plants species demonstrated threshold cycles (Ct) of 16.13 ± 0.12 to 16.25 ± 0.23 for canine DNA and negative results for the others in a 40-cycle reaction. The assay was tested for the quantification of up to 0.01% canine meat in deliberately spiked chicken nuggets with 99.7% PCR efficiency and 0.995 correlation coefficient. The analysis of the actual and qPCR predicted values showed a high recovery rate (from 87% ± 28% to 112% ± 19%) with a linear regression close to unity (R² = 0.999). Finally, samples of three halal-branded commercial chicken nuggets collected from different Malaysian outlets were screened for canine meat, but no contamination was demonstrated.

KEYWORDS:

• qPCR assay
• canine species
• nugget formulation
• halal meat
• food adulteration

Additional information

Funding

This research was supported by University of Malaya research grants to Professor Sharifah Bee Abd Hamid [grant number TR002B-2014B], Professor W. J. Basirun [grant number GC001C-14SBS] and Dr M. E. Ali [grant number GC001A-14SBS].